Hi,
Your query below is most likely including referrals that are not
associated to adCampaigns. "not set" is just a place holder for
referrals that don't have a particular filed set. Google Analytics
uses 5 dimensions to define a referral source (Campaign, Source,
Medium, Keyword, Content). The first 3 are required parameters.
If a user comes from a referral, GA tracks them as:
Campaign = "not set"
Source = referring domain
Medium = referral
Keyword = "not set"
Content = "not set"
If you link your AdWords and Analytics accounts and a user comes from
a paid ad:
Campaign = "Campaign name in AdWords the keyword belongs to"
Source = "google"
Medium = "cpc"
Keyword = "term you bid on"
Content = "first line in AdWords creative that was used"
You can get around not showing the "not set" by using a filter to
exclude keywords with "(not set)" in your query.
-Nick